[llvm] [RISCV][GlobalISel] Lower i8 bitreverse using brev8 with Zbkb (PR #199469)

[Bogdan Vetrenko via llvm-commits]

bv2k4 wrote:

thanks, addressed all suggestions and regenerated the test checks after switching to buildAnyExt

https://github.com/llvm/llvm-project/pull/199469